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  1. This guide will take you through the replacement of the hotend PTFE tube on the Original Prusa MINI.
    • This guide will take you through the replacement of the hotend PTFE tube on the Original Prusa MINI.

    • All necessary parts are available in our eshop shop.prusa3d.com

    • Note that you have to be logged in to have access to the spare parts section.

  2. 1.5mm Allen key (1x) Needle-nose pliers / tweezers (1x) Wrench 10 mm (1x)
    • 1.5mm Allen key (1x)

    • Needle-nose pliers / tweezers (1x)

    • Wrench 10 mm (1x)

    • Cloth or piece of fabric 15x15 cm (1x)

    • The cloth will be used to protect the heatbed. You can use any similar material.

  3. Make sure the that:
    • Make sure the that:

    • The filament is unloaded from the printer.

    • The printer parts - print head and heatbed are cooled down at room temperature!!!

    • The printer is turned off and unplugged from the socket.

  4. Before these steps, it is recommended to protect the heatbed!
    • Before these steps, it is recommended to protect the heatbed!

    • Take off the magnetic steel sheet.

    • Use any cloth or piece of fabric, which is thick enough and cover the heatbed. This will ensure you won't damage (scratch) the surface during the disassembly.

  5. Loosen the upper fitting and remove the long PTFE tube from the hotend. Release and remove the lower fitting from the heatsink.
    • Loosen the upper fitting and remove the long PTFE tube from the hotend.

    • Release and remove the lower fitting from the heatsink.

  6. Carefully pull out the old PTFE tube from the heatsink using pliers or tweezers. Use your phone LED flash or similar device to shine into the hole from the top of the print head. Take a look inside and check there is no filament in the bottom of the heatbreak. It must be clean and you should see only the metal surface inside. Open the full-size image if needed. A clean print head is essential for successful prints. Double-check, there is no filament inside!!!
    • Carefully pull out the old PTFE tube from the heatsink using pliers or tweezers.

    • Use your phone LED flash or similar device to shine into the hole from the top of the print head. Take a look inside and check there is no filament in the bottom of the heatbreak. It must be clean and you should see only the metal surface inside. Open the full-size image if needed.

    • A clean print head is essential for successful prints. Double-check, there is no filament inside!!!

  7. For the following steps, please prepare: New hotend PTFE tube (1x)
    • For the following steps, please prepare:

    • New hotend PTFE tube (1x)

  8. Insert and push the new PTFE tube into the heatbreak all the way down. Orientation of the PTFE tube installation does not matter. Both ends are symmetrical. Loosen tree screws on the side of the heatsink with 1.5 Allen key.
    • Insert and push the new PTFE tube into the heatbreak all the way down.

    • Orientation of the PTFE tube installation does not matter. Both ends are symmetrical.

    • Loosen tree screws on the side of the heatsink with 1.5 Allen key.

    • Push the nozzle up. You must see the PTFE tube moving up a bit.

  9. Mount the "lower" fitting to the top of the heatsink. Screw it all the way, but don't tighten it. As soon as you reach the end of the thread, release it slightly by 1/4 of turn (90 °). Push the heaterblock up against the fitting with a reasonable force. No need to bend the entire axis. This will pre-stress the PTFE tube inside. Now, it is important to keep the pressure. Make sure the heaterblock is aligned with the heatsink. If not, realign it, but keep the pressure.
    • Mount the "lower" fitting to the top of the heatsink. Screw it all the way, but don't tighten it. As soon as you reach the end of the thread, release it slightly by 1/4 of turn (90 °).

    • Push the heaterblock up against the fitting with a reasonable force. No need to bend the entire axis. This will pre-stress the PTFE tube inside. Now, it is important to keep the pressure.

    • Make sure the heaterblock is aligned with the heatsink. If not, realign it, but keep the pressure.

    • While holding the heaterblock from below (pressing the tube inside), tighten all three grub screws.

    • Now, you can release the heaterblock. Make sure it doesn't move. If so, the grub screws were not tightened properly. Release them and return to the beginning of this step.

    • It is crucial there is no gap between the PTFE tube and other parts of the hotend. This is why we are "pre-stressing" it.

  10. Finish tightening of the "lower fitting", you should do 1/4 (90 °) turn to compensate for the turn we did in the previous step. Mount and tighten the upper fitting with the long PTFE tube.
    • Finish tightening of the "lower fitting", you should do 1/4 (90 °) turn to compensate for the turn we did in the previous step.

    • Mount and tighten the upper fitting with the long PTFE tube.

    • ...and it’s done! Enjoy your printer ;)

Finish Line

One other person completed this guide.

Vojta Z.

Member since: 06/26/2019

8 Guides authored

3 Comments

Step 6 question. My printer head has filament inside of it when I check with a light. It is clearly azure blue and not brass just like the prusament PLA that I was using. What is the recommended way to remove this blockage of filament? Heat nozzle and use the small >.4mm gouging tool provided? I will try that out.

miniprinterman2020 - Reply

I had the exact same problem after only 3 prints.

My Azur Blue Filament was stuck inside.

To remove it I pull out the PTF tubing that is inside nozzle.

Set temperature to 250"C

Then I pushed in (without the PTF tubing )filament until it start to purge on the other side then I set the temperature 0 and let it cool down.

After I put the temperature to 100"C and when it reach the set temp I pull out the filament whit all the junk.

It was 100% clear. So I put everything back and hope I won’t get this problem anymore.

Alexandru Knizel -

Update: The small >.4mm metal stick did nothing as it would simply go through the hot (215C) glass transitioned PLA. What worked is I used a small allen key and jammed it through the backside of the nozzle while hot and the PLA extruded through nicely, took 2-3 attempts to get it all. Ended up getting a shaving of brass because I pushed a little hard. I think in retrospect 250C would lower viscosity to have PLA flow out of the nozzle, though I doubt that would work because the nozzle is .4mm and that would require back pressure to flow through orifices that small.

Great, now its clean. This problem shouldn’t have been an issue had the PTFE tube been assembled properly the first time unfortunately. I hope I can use this 2nd PTFE tube and push the nozzle/hot-end up so there won’t be a gap between hot end and nozzle.

miniprinterman2020 - Reply

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